Qualitative research is evidence, too

Abstract

With the current emphasis on accountability for outcomes and the need for objective evaluation of efficacy of interventions, physiotherapists are increasingly using evidence from research as a source of information to support clinical decision making. The concept of evidencebased practice has been adopted widely in physiotherapy with much work devoted to encouraging the transfer of research results into clinical practice. Under the definition developed by Sackett et al (2000) – a group of clinical epidemiologists – evidence-based practice requires the integration of three components: patient values, clinical expertise, and best evidence from research. Best evidence from research is defined as ‘clinically relevant research… [about the] accuracy and precision of diagnostic tests, the power of prognostic markers, and the efficacy and safety of therapeutic, rehabilitative, and preventive regimens.’ Increased focus on using evidence from research as a source of information for clinical practice has led to the development of hierarchies for evaluating research rigour (Guyatt and Rennie 2002, Higgins and Green 2005, Butler et al 1999). Evidence hierarchies are most often based on criteria for rigour developed for quantitative research designs. Design is ranked according to the extent that the study is internally valid or free from sources of bias, with large randomised controlled trials providing the highest level of evidence and physiologic studies and unsystematic clinical observations providing weaker evidence. Qualitative research is excluded from most prominent hierarchies because qualitative and quantitative research have different underlying philosophies, methods, and criteria for judging quality. However, it should not be inferred from this exclusion that rigorous qualitative research is a less valuable form of evidence or that research employing qualitative methods cannot be used to inform clinical practice. In fact, the Cochrane Qualitative Research Methods Group is exploring whether and how studies using qualitative methods can be included in systematic reviews. As clinicians, we know that implementation of interventions in real-world situations requires knowledge about patients’ values and experiences, contextual variables that influence how interventions are delivered, and the difficult-toquantify human aspects of clinical practice – what Guyatt et al (2000) refer to as the broad perspective offered by the humanities and social sciences. Since selection of research methods should be based on their ‘best fit’ with the research questions, qualitative methods (used alone or in a mixedmethod design) provide a systematic approach to producing knowledge about the behaviours, values, and experiences of patients, their families, and clinicians. Qualitative research can provide clinically-relevant information about patient values and experiences. In the reality of clinical practice, knowing why patients choose not to participate in an intervention is as important as knowing about its efficacy. Efficacious interventions will have limited therapeutic value if patients cannot or